This invention relates to the utilization of exhaust gases from a hydrocarbon fuel combusting apparatus for enhancing plant growth.
It is known that the growth of plants can be enhanced by subjecting them to an atmosphere containing CO.sub.2 in amounts larger than found in ambient air. Furthermore, in many regions of the world it is desirable or necessary to provide heat to obtain optimum plant growth in all seasons. The exhaust gases from a hydrocarbon combusting apparatus, such as an engine or heater, contains both heat and CO.sub.2. However, to date, no entirely satisfactory means has been devised to utilize both the heat and the CO.sub.2 for plant growth, and the exhaust gases are normally wasted. One of the difficulties with such exhaust gases, is that they contain, in addition to CO.sub.2, other gases which are toxic to plants, notably NO.sub.x (NO.sub.2, NO) and in some cases SO.sub.2. Although heat exchangers can be used to extract the heat from exhaust gases, and known processes could be used to remove noxious gases, the additional costs involved reduce the attractiveness of using exhaust gas for its heat and CO.sub.2 content.